The objective of this proposed project is to identify and describe specific sedentary characteristics and sedentary profiles associated with subsequent functional loss in older adults at elevated risk for poor function. The proposal responds to PA-13-237 regarding the identification of modifiable risk factors such as sedentary lifestyles. We will conduct a secondary data analysis of the Osteoarthritis Initiative (OAI) database, which is a cost effective use of publicly available data on a sample of older adults at elevated risk for functional loss due to knee osteoarthritis or knee osteoarthritis risk factors (eg., obesity, knee pain). Reducing sedentary behavior is recommended as a strategy to prevent poor health outcomes. However, it is not known which aspects of sedentary behavior are problematic. The OAI public data provide objective physical activity assessments from accelerometer monitoring and longitudinal clinical assessments to pursue the following aims: Aim 1. Describe Daily Sedentary Behavior Characteristics Describe the distribution of daily sedentary behavior characteristics: 1) total sedentary time, 2) maximum duration of sedentary bouts (sessions), 3) sedentary break frequency, and 4) physical activity duration/intensity level during sedentary breaks. Aim 2: Identify Distinct Sedentary Profiles Identify the presence of distinct baseline sedentary profiles (i.e., combinations of sedentary behavior characteristics in Aim 1) and evaluate their distribution. Latent profile analysis will be used to identify sedentary profiles. Aim 3. Association of Sedentary Behavior Characteristics and Profiles with Functional Loss Evaluate the relative strength of association of sedentary behavior characteristics (Aim 1) and sedentary profiles (Aim 2) with subsequent functional loss at year 2. Results from this study will expand the understanding of sedentary behavior characteristics, sedentary profiles, and their association with subsequent functional loss in order to inform the development of more effective interventions to sustain function and independence of older adults.